If there was a grain of doubt remaining that air quality affects health, a study in the current issue of the New England Journal of Medicine should remove it: Clean air extends life.

In fact, improvements in air quality alone over the last 20 years have increased the average life expectancy in the United States by almost five months. In scientific terms, that is significant.

For the study released Thursday, scientists at Brigham Young University in Utah and at the Harvard School of Public Health looked at government data between 1978, when the stricter Clean Air Act went into effect, and 2001. They tracked particulate levels in 51 U.S. cities and compared them to death records and census data, taking into account issues such as smoking habits, income, education and population movement.

On average, they found, as particulate matter levels fell, Americans’ life spans increased an average of 2.72 years, with as much as 4.8 months of that attributed to the better air. Cities that had the greatest air quality improvement saw greater gains in life expectancy.

Of special significance to us living in the Cumberland Valley is the research on the effects of fine particulate matter. This is of serious concern in Southcentral Pennsylvania, where local doctors in recent years noticed an increase in asthma and respiratory problems among their patients.

High levels of particulates, especially PM 2.5, are so small they penetrate deep into the lungs and stay there, carrying with them toxic chemicals. PM 2.5 is produced by factories, power plants and diesel-powered vehicles, and it is difficult not to draw a connection between the increased traffic that moves through our area and what the doctors were seeing.

In 2005, a group of concerned citizens formed the Clean Air Board to draw attention to the problem – which we now know was not imagined. In 2007, a health status assessment conducted by the Carlisle Area Health and Wellness Foundation that found 13 percent of adults in the Carlisle area reported having asthma — up from 10.4 percent in the 2002 study. In early 2008, the Asthma and Allergy Foundation of America listed the area 14th on its list of most challenging places to live with asthma.

Finally, in December 2008, the U.S. Environmental Protection Agency formally designated Cumberland County as a county not meeting federal air quality standards.

In light of this new study, we should be redoubling our efforts to turn the tide of air quality here. We can do that by educating ourselves and working with our local legislators, congressmen and senators to keep the issue on their agendas.

The efforts of the Clean Air Board also deserve support. Its members were instrumental in passage of anti-idling legislation in 2008 and in bringing a permanent PM 2.5 monitor to the county, in partnership with Carlisle Regional Medical Center and The Sentinel. (Real-time readings are available atwww.cumberlink.com.)

If it weren’t for the concerned citizens of the Clean Air Board, we would be far behind in the battle for healthier lives.